Contusion of the brain's surface occurs when the brain strikes the bone within the skull.  Contusions can occur at the tips of the brain: frontal (front), temporal (side), and occipital (rear). Large contusions may be seen on CT scans or MRIs as large bruises.

Areas of contusion that are visible will be surrounded by a zone of swelling, know as "edema."  If this swelling is great enough, it may cause changes in consciousness, and in severe cases, may be life threatening.

However, contusions are often microscopic or pin-point hemorrhages and are too small to be seen on cur4ently used CT or MRI imaging tests. There is hope that in the near future technological advances with CT and MRI tests will allow better visualization of these hemorrhages.